Detachable bit



All@ 18, 1936? A P. LIDDlcoAT 2,051,306

DETACHABLE BIT Filed Feb. 16, 1955 Patented Aug. 18, 1936 UNITED STATES PATENT OFFICE Application February 18, 1935, Serial No. 8,894 In Canada February 1'l, 1934 9 Claims.

In the present invention I have devised a detachable bit, adapted to be readily mounted on the shank of a rock cutting drill rod. which is so constructed that the successive blows which are received by the shank of the drill rod are transmitted to the sleeve or bit, in rock cutting, or similar uses of the invention. The detachable bit also readily locks itself on the shank of the drill rod by impacts received from the machine operating the drill rod. 'I'he locking action referred to is effected by the riveting and bending action of a plurality of lugs on the end of the drill rod hammering over the upper edge of the sleeve or bit to form a collar, or partial collar, on said sleeve or bit. This feature will be more fully described hereinafter.

In the present invention the impact, transmitted to the bit when the drill rod is operated, is taken practically over the blades of the bit, thereby tending to drill a straight hole into the rock or other material being drilled, as will be explained later.

The torsion of rotation oi' the bit when in operation is taken by the ilat sides of the bit shank which lits into the sleeve recess, as will also be described later.

The type of bit under consideration also keeps centralized under all working conditions with the direction of the drill rod. The said bit can be easily and cheaply manufactured either by pressing, or drop forging without subsequent machining. The fact that the inner walls of the sleeve or bit are vertically parallel also facilitates the manufacturing operations in making the bit. This and other features of the invention will be described as the specification proceeds.

In the accompanying drawing, I have shown a physical embodiment of the present invention, constructed according to the best mode I have devised for same, in which:-

Figure 1 is a side elevation of the shank of a rock cutting drill rod with the detachable bit mounted thereon.

Figure 2 is a plan view of the bit, per se.

Figure 3 is a vertical section of the device, partly in elevation, taken on line 3-3, of Figure 2.

Figure 4 is a bottom view of the. drill ro shown in Figure 3.

Figure 5 is a bottom view of the detachable bit shown in Figure 2.

In the drawing I indicates a rock cutting drill rod which is provided with a specially formed end 2 adapted to engage into the recess 3 formed in the detachable bit or sleeve 4. The sleeve 4 is preferably provided with a plurality of horizontally disposed cutting edges 5, E, 1, 8 of the angular shape shown in Figures l, 3 and 5 of the drawing. 'The recess 3 may be made either with a at bottom 9, or a partially or fully concave bottom III, as desired. 'I'he said recess when first placed in contact with the bottom end of the drill rod, is provided with vertically parallel side walls II, I2, etc. The bottom end 2i of the drill rod is formed to have a complementary shape to the cross-sectional outline of the recess 3 of the bit, which in the drawing ls octagonal in shape, but may be of cruciform, square, hexagonal, oval or any other similar cross-sectional outline. It will be noted that the bottom end I3 of the`part 2i is slightly less in size than the size of the recess, so that the end of the drill rod may be easily inserted in the recess of the bit. 'I'he part 2 of the rod I is upset to form a plurality of lugs or enlargements I4, I5, I6 etc., each having a recess I8 formed therein, as clearly shown in Figure 3 of the drawing. The purpose of these recesses is to provide a means of locking the bit 4 on to the shank 2l of the rod I. It will be seen that the successive blows received by the rod I will tend to turn portions of the upper edge I9 of the bit l inwardly and thus lock the bit .to the shank 2l of the drill rod, and yet when it is desired torremoveY the bit 4 this can be done by merely tapping the exterior surface of the bit in several places with a hammer. It is found that by having the bottom of the recess 3 of the bit formed in a partially concave shape as indicated at I0 Figure 3 of the drawing, the blows transmitted by the rod I to the bit are delivered on the outer circumference of the bottom end I3 of the shank, thus delivering circumferential impacts to the bit, which is found to be a working advantage in practice. I

The passages and 22, the former in the bit and the latter passing through the drill rod I and the shank 2l are designed to permit water to ow through the rod and bit, and have direct play on the face of the rock being drilled, to wash away rock chippings, thus preventing rock dust from injuring the operators of the device.

It will be noted that by having the bit readily detachable from the drill rod, said bit may be replaced by freshly sharpened bits frequently, as is necessary in toolsoi the kind under consideration.

The depth of the recess 3 in the bit is preferably made slightly greater than the length of the shank 2l on the rod as this permits the force of the blows from the rod at the commencement of operation, to do the bending and riveting. of the lugs or enlargements I5, I6 etc., over the top edge I9 of the bit. and thereby form a partial collar on the bit which locks the latter to the shank of the drill rod. After the attachment has been accomplished between the bit and the shank of the rod, the blows of the rod are delivered directly on the bottom 9 of the bit recess, which thereafter forms a seat for the bottomface of the shank and transmits the blows directly into the material-of the bit. The cross-sectional shape of the bit recess may be, as mentioned above, of varying shape to correspond with the cross-sectional shape of the shank of the drill rod depending on theV users, or manufacturers requirements. The shank construction is of such a shape that it may be readily hand forged, machine forged. or made in a shaper or milling machine, and it can be made having a breaking strength equal to, or greater than, the main body of the drill rod. The shank is hardened and tempered after .same is made into proper form.

The tempering of the bit is confined to the actual cutting faces I, l, 1, l of same, while the body portion of the bit is permitted to remain in a non-tempered state, in order to minimise wear on the lugs and shank of the drill rod.

It will be noted that due to the curved bottom it of the bottom of the recess I of the bit the impact from the drill rod is delivered on the circumference of the recess and delivered directly on the blades or teeth Ll, 1, l, and this tends to drill a straight holein the rock being drilled,- and keeps the bit centralized .with reference to the direction of impact of the drill rod.v f

It is evident that when the drill rod is opere ated there is a movement of rotation which is transferred to the bit and in order to accomplish this purpose theend of the rod shank and the vertical recess in the bit. are made of a shape such as hexagonal, octagonal, or. ov'al etc., so that th'e `torsion of rotation of the drill rod can be kproperly transmitted to the bit. Also as referred t0 in the preamble of this speciilcation, the -fact that the'inner walls oi the bit recess are vertically parallel facilitates the manufacturing operations in making the bit.

I claim:

1. In a device of the class descriped. a drill rod, a bit having a number of cutting teeth, and a shaped recess formed therein. a shaped shank on the end of the drill rod adapted to i'it the bit recess and enable the blt to be revolved when the drill rod is in operation, and means for detachably mounting the bit on the rod shank, comprising a plurality of curved depending lugs formed on the drill rod adapted to bend portions of the than the depth of the bit recess, and a plurality of depending recessed lugs formed on the drill rocl,v adapted when the drill rod is at first operated to bend over portions of the upper edge of the bit, to secure the latter on to the shank, and thereafterto permit the bottom end of the drill rod shank to deliver circumferential impacts on the partially concave bottom of the bit recess.

' 3. In a device of the class described, a drill rod, a number of upset and depending lugs formed on the drill rod, a bit having a number of cutting teeth thereon and a shaped-recess formed therein, a shaped shank on the end of the drill rod adapted to ilt into the bit recess and having a number of recesses therein, each of which is opposite to and in proximate relation with one of` the depending lugs of the drill rod, said shank being of slightly less length than the depth of the' bit recess for the purpose of permitting the said depending lugs to turn portions of the upper edge of the bit inwardlyand `hold the latter on the 7shank when the drill rod is at ilrst operated, and il thereafter to permit the bottomv of said shank Ato seat itself in the bottom of the bit recess.

,of the bit inwardly into a shank recess, and

thereby provide a means of holding the bit on totheshankofthedrillrod.

5. A drill rod adapted to be connected to a bit, a plurality of depending lugsfformed thereon, and a shaped rod shank having a plurality of recesses therein, adjacent to said lugs and forming therewith a md and bit locking means, adapted to bend portions of the top edge of the blt inwardly about the shank when the rod and bit are subjected to impact during the normal operation of the drill rod.'

8. In a device of the class described, a drill rod. a detachable bit having a shaped recess formed therein, aconcave bottom formed in lthe bit recess, a shank on the end of the drill rod, adapted to fit the bit recess, and .having a shank length slightly less than the depth of the bit recess. and a plurality of depending recessed lugs formed on the drill rod.adapted when theV drillrod is operated to-bend over portions of the upper edge .of the bit, to 'secure the latter on tothe shank, and thereafter permit the bottom end of the shank to seat itself in the concavebottom of the bit recess.

'1. A device of the class descrlbed,comprising a drill rod having a shaped shank and having lugs overhanging said shank with undercut recesses formed therebetween, and a blt having a conformingly shaped socket for receiving said shank and having an upper wall edge of deformable material, said upper wall edge being so proportioned as to be forced into said recesses and wedgingly secured therein by the impacts incident to the operation of said device.v

8. A device of the classdecribed, comprising a drill rod having a shank provided with substantially plane parallel faces and with lugs over- 55 hanging certain of said faces and forming undercut recesses therewith, a bit having a conformingly shaped socket for' receiving said shank and havingan upper deformable socket wall portion adapted to be forcibly deformed to extend into 60 and engage with the surfaces of said undercut recesses. i

9. A drilling device comprising a rod member and a bit member having male and female parts, the male part being of substantially constant 65 cross section throughout its contacting extent with said female part, the female part having deformable edge portions and the m'ale part having shoulders provided with undercut recesses for receiving and lockingly engaging said edge portions of said female part member by deformation of said portions under the impacts occasioned by operation of said device.

PERCIIL LIDDICOAT. 

